Re: Language negotiation
This is very much personal preference:
I agree with you in general that the site should detect and eventually adjust based on location on the basis that maybe (maybe) most people want this.
However personally I hate it when sites do this automatically. After all this behavior is something the creator of the site decided "it's what everyone wants". But it is not. I'd rather manually change language, and this means the language button/dropdown should be prominently shown, or let browser do this for me after explicitly asks me if I want it to happen (and I do this on per site basis). Of course this uses some sort of online translation like Google Translate.
And this is the proper behavior - we detected you are in X area and your spoken language is Y, do you want to see this page in Y language variant... or something like this.
So not assume what people want.
If XC adds such a functionality I'd rather see it as an option for customer to make a choice and not something forced on them.